We identify that quantum coherence is a valuable resource in the quantum heat
engine, which is designed in a quantum thermodynamic cycle assisted by a
quantum Maxwell's demon. This demon is in a superposed state. The quantum work
and heat are redefined as the sum of coherent and incoherent parts in the
energy representation. The efficiency of the heat engine potentially can exceed
the Carnot efficiency due to the coherence consumption of the demon. In
addition, we also discuss a heat engine driven by quantum coherence. This

Author(s): Wen Wei Ho, Soonwon Choi, Hannes Pichler, and Mikhail D. Lukin
We analyze quantum dynamics of strongly interacting, kinetically constrained many-body systems. Motivated by recent experiments demonstrating surprising long-lived, periodic revivals after quantum quenches in Rydberg atom arrays, we introduce a manifold of locally entangled spin states, representabl...
[Phys. Rev. Lett. 122, 040603] Published Tue Jan 29, 2019

Author(s): Tom Douce, Damian Markham, Elham Kashefi, Peter van Loock, and Giulia Ferrini
Continuous-variable (CV) devices are a promising platform for demonstrating large-scale quantum information protocols. In this framework we define a general quantum computational model based on a CV hardware. It consists of vacuum input states, a finite set of gates—including non-Gaussian elements—a...
[Phys. Rev. A 99, 012344] Published Tue Jan 29, 2019

Author(s): Vladimir M. Stojanović
We investigate the feasibility of single-shot Toffoli- and Fredkin-gate realizations in qubit arrays with Heisenberg-type exchange interactions between adjacent qubits. As follows from the Lie-algebraic criteria of controllability, such an array is rendered completely controllable—equivalent to allo...
[Phys. Rev. A 99, 012345] Published Tue Jan 29, 2019

Chromatin remodelers are molecular motors which actively displace nucleosomes on chromatin. Recent
results on the structural properties of these motors indicate that the displacement of nucleosomal
DNA corresponds to an inchworm motion induced by the generation and propagation of twist defects.
Here we show that this basic action mechanism can be described by a coarse-grained active Brownian
dimer (ABD) model, thereby quantitatively rationalizing the notion of inchworm motion. The model

Various inequalities (Boole inequality, Chung–Erdös inequality, Frechet inequality) for Kolmogorov
(classical) probabilities are considered. Quantum counterparts of these inequalities are introduced,
which have an extra ‘quantum correction’ term, and which hold for all quantum states. When certain
sufficient conditions are satisfied, the quantum correction term is zero, and the classical version
of these inequalities holds for all states. But in general, the classical version of these

The Fokker–Planck equation is a key ingredient of many models in physics, and related subjects, and
arises in a diverse array of settings. Analytical solutions are limited to special cases, and
resorting to numerical simulation is often the only route available; in high dimensions, or for
parametric studies, this can become unwieldy. Using asymptotic techniques, that draw upon the known
Ornstein–Uhlenbeck (OU) case, we consider a mean-reverting system and obtain its representation as a

Author(s): Vikesh Siddhu
Using a Bayesian methodology, we introduce the maximum a posteriori probability (MAP) estimator for quantum state and process tomography. We show that the maximum likelihood, the hedged maximum likelihood, and the maximum likelihood-maximum entropy estimator, and estimators of this general type, can...
[Phys. Rev. A 99, 012342] Published Mon Jan 28, 2019

Author(s): Lv-Jun Li, Fei Gao, Zhi-Chao Zhang, and Qiao-Yan Wen
In this paper, we study the local distinguishability of mutually orthogonal product quantum states with entanglement as a valuable resource. We present protocols in which entanglement is used more efficiently than in the previous protocols presented by Zhang et al. [Phys. Rev. A 97, 022334 (2018)]. ...
[Phys. Rev. A 99, 012343] Published Mon Jan 28, 2019

Author(s): Jan Klaers
A future computer might reduce heat production by timing operations to match naturally occurring temperature swings within the device.[Phys. Rev. Lett. 122, 040602] Published Mon Jan 28, 2019